Piston.



, PATENTED MAR. 17, 1903.

R. MORRILL.

PISTON. APPLICATION FILED FEB. 6, 1902.

N0 MODEL.

UNITED STATE PATENT OFFICE.

ROLAND MORRILL, OF BENTON HARBOR, MICHIGAN.

PISTON.

SEEGIFICATION forming part of Letters Patent No. 7 23,005, dated. March17, 1903.

Application filed February 6, 1902. Serial No. 92,817. (No model.)

To aliwhom it 777/(I/y 007t0077b:

Be it known that LRQLAND MoRR1LL,a citizen of the'United States,residingat Benton 'Harbor, in the county of Berrieri and State ofMichigan, have invented certain new and useful Improvements in Pistons,of which the following is a specification.

The present invention relates to pistons generally and may be embodiedin a piston to which power is applied and which in turn exerts itspressure upon a fluid, as in a pump or compressor, or it may be embodiedin a piston upon which a fluid under pressure exerts its pressure andwhich in turn exerts its pressure upon some other part, as in an engineor other motor. I desire to have it understood, therefore, that theinvention is not limited to the character of the machine in which thepiston is used, but that, on the contrary, it is concerned only with thecon-. struction of the piston itself.

Both the construction and mode of operation of a cup-leather packing arewell understood in the'art. It is automatic in its operation to theextent that its pressure against the walls of the cylinder isproportional to the outward pressure of the fluid upon it, so thatduring the working stroke it is forced outward with greater or lessforce, while during the return stroke it is allowed to contract, therebyreducing the friction to a minimum.

The principal object of the present invention is to provide a piston anda packing therefor of such construction that while act-,

ing somewhat upon the above-described principle' of the cup-leatherpacking it shall at the same time have the additional advantage of aninherent ability to automatically expand and contract in proportion tothe pressure of the fluid upon it supplemented by means adapted to beoperated manually for taking up excessive wear.

Another object of the invention is to provide a piston which is hollowto the extent that the fluid under pressure may enter it and which haslateral openings presented outward and covered by the packing, so thatthe fluid under pressure entering the cylinder and passing outwardthrough said openings will act upon the packing to expand it inproportion to its own pressure.

Another object of the invention is to provide a piston with a bodyportion having a shoulder against which the packing reacts and. afollower mounted loosely upon said body, so as to be capable of slidingthereon freely, the follower also being provided with a shoulderengaging the packing, so that the pressure of the fluid upon thefollower causes the follower to react upon thepacking and expand it inproportion to the pressure of the fluid upon the follower. v

Other objects of the invention will appear hereinafter. i

In the accompanying drawings, which are made a part of thisspecification, Figure 1 is a view, partlyin side elevation and partlyincentral section, of a piston embodying the invention. Fig. 2 is a viewthereof, partly in plan and partly in transverse section. Fig. 3 is aview of the follower, partlyin side elevation and partly in centralsection. Fig. 4 is a view of the adjusting-ring, partly in sideelevation and partly in central section.

What may be termed the body of the piston is represented by the letterA. It comprises a cylindrical portion a, that is adapted to fit thecylinder more or less closely, a tapering or frusto-conical shoulder a,a diaphragm a,and a shell a which is tubular, save that it has throughit a series of lateral openings a which are preferably elongated in thedirection of its length and extend,

preferably, from the diaphragm a to within a short distance of the endof the shell a This body portion of the piston may have a pair ofperforated ears or lugs B, through the medium of which the piston-rod orother device for transmitting movement or power to or from the piston isattached. Mounted loosely upon this shell, so as to be capable ofsliding thereon, is a follower 0, comprising a short cylinder or ring 0,a tapering or frustoconical shoulder 0, provided with openings 0, and acylindrical portion 0 which'fits the cylinder about as does thecylindrical portion a of the body A. l

The follower O is mounted upon the shell a so that while it fits snuglyit is nevertheless capable of moving freely thereon longitudinally'inresponse to pressure upon it in the direction of the length of thecylinder or the movement of the piston.

The exterior of the shell a is threaded, and onto it is turned athreadedring D, provided with studs (Z or other means for receiving a spanner orother tool, whereby the ring may be turned up to force the follower 0toward the shoulder a of the shell for taking up or compensating forwear.

Between the tapering faces a and c of the body A and follower C isplaced a mass E of packing material of some suitable sort. I do notlimit myself to a packing material of any particular kind, but prefer touse loose Wicking, as it is cheap and has been found to be absolutelyeffective in accomplishing the objects of the invention. Asillustratedin the drawings it is wound around the shell a so as to completely fillthe space bounded by the two tapering shoulders a and c, the shell (1and the inner surface of the cylinder. When so arranged, it is manifestthat fluid under pressure on what may appropriately be termed theworking side of the piston entering the hollow shell or will passoutward through the openings a and contact with the mass E of packingmaterial. This material being elastic will be expanded outward laterallyand will be forced into more or less intimate contact with the innersurface of the cylinder in which the piston fits, and its outwardpressure will of necessity be proportional to the pressure of the fluidupon it, so that in this respect the action of the packing will beautomaticthat is to say, it will have heavy or light frictional contactwith the cylinder, accordingly as heavy or light frictional contact isrequired. When the piston is making its working stroke, the frictionalcontact of the packing will be proportional to the pressure of the fluidupon the piston, and when the piston is making its return stroke (thepacking being entirely relieved of the pressure of the fluid) thepacking will contract by its own elasticity and its friction with thecylinder will be reduced to a minimum.

The tapering or conical form of the shoulder 0 tends to give it awedging action and increase the diameter of the packing as the followerO is forced onto the body of the piston, and it also has the advantageof reducing the lower margin of the body of packing to a thin lip orfeather-edge, thus making it extremely sensitive to the action of thefluid which reaches it through the openings 0.

In the ordinary operation of the piston there will be more or lessmovement of the follower O relatively to the body A. As the piston ismaking its working stroke the pressure of the fluid will tend to movethe follower toward the shoulder 01. of the body A, and this in turnwill tend to expand the packing. When the piston is making its returnstroke, the follower being wholly or substantially relieved of thepressure of the fluid upon it, the packing, following the laws ofelasticity, will tend to contract and move out of contact with the wallsof the cylinder, and

these-operations will be repeated at each and every stroke of thepiston.

Having thus described my invention, the

following is what I claim as new therein and desire to secure by LettersPatent:

- l. A piston having a hollow part provided with openings presentedoutward and a body of elastic packing material surrounding said hollowpart and covering said openings, substantially as described.

2. A piston having a hollow part provided with openings presentedoutward, a follower slidably mounted upon said hollow part and a body ofelastic packing material surrounding the hollow part'and covering saidopenings, the piston being provided with a shoulder against which thepacking bears, substantially as described.

3. A piston having a hollow part provided with openings presentedoutward, a body of elastic packing material surrounding said hollow partand having an inclined, or tapering shoulder engaging said packingmaterial, substantially as described.

4. A piston having a body portion, a body of elastic packing materialsurrounding said body portion, and a follower slidably mounted upon saidbody portion and having openings covered by the packing material,substantially as described.

5. A piston having a body portion, a body of elastic packing materialsurrounding it, and a follower slidably mounted uponthe said bodyportion and having an inclined shoulder engaging the packing, saidshoulder being provided with openings, substantially as described.

6. A piston having a hollow portion provided with openings presentedoutward, a body of elastic packing material surrounding said hollowportion and covering said openings, a follower slidably mounted uponsaid hollow portion and having a shoulder engaging the packing, and athreaded ring turned onto said hollow portion and engaging the followerfor holding it in place, substantially as described.

7. A piston having a body portion comprising a cylindrical portion a, atapering shoulder a, the diaphragm a, and a hollow shell a provided withopenings a the follower C slidably mounted upon the hollow shell a andhaving the tapering shoulder 0' provided with openings 0 and acylindrical portion 0 and a body of elastic packing material filling thespace between the shoulders at and c, substantially as described.

ROLAND MORRILL.

Witnesses L. M. HOPKINS, BELLA EVANS.

IIO

